1. Field of the Invention
The present invention relates to an endoscope shape detector that detects the insertion shape of the endoscope and others using magnetic-field generating elements and magnetic-field detecting elements, and that displays them.
2. Description of the Related Art
In recent years, endoscope shape detectors have been used that detect the insertion shape of the endoscope inserted in a body cavity using magnetic-field generating elements and magnetic-field detecting elements, and that displays it by display means.
For example, Japanese Unexamined Patent Application Publication No. 8-107875 discloses an apparatus that detects the shape of the endoscope using magnetic fields, and displays the detected endoscope shape.
However, the detection range of magnetic-field detecting elements is finite because of the outputs of magnetic generating elements and sensitivities of magnetic detecting elements, and therefore, if the magnetic generating elements are located at positions at least a definite distance away from the magnetic detecting elements, a practicable detection accuracy cannot be obtained.
For example, in the arrangement disclosed in the Japanese Unexamined Patent Application Publication No. 8-107875, if the inserted portion of the endoscope of which the shape is to be detected moves to a position away from the magnetic detecting elements, a problem occurs that the actual shape of the inserted portion differs from the displayed shape.